192 IOWA ACADEMY OP SCIENCE Vol. XXVI, 191',) 



one place an abundance of F. graminis on red top and timothy. 

 Mr. Dadant informed me that there was a barberry hedge 150 feet 

 away, which of course accounted for the rust infection at this point. 



As other instances where rust could be directly connected with the 

 barberry, mention might be made of Scott, Clinton and Dubuque 

 counties, but these have been considered by Melhus, Kirby and 

 Durrell in a paper on stem rust of cereals. 



In conclusion, I have always believed that the barberry is an im- 

 portant factor in the production of rust, but not the only one. I 

 felt that possibly, under some conditions the mycelium may be 

 perennial, or that the uredo spores may be viable in the spring or that 

 there is a possibility that rust may move northward as the season 

 advances. I am of the opinion that our rust epidemics in the north 

 can be attributed mainly to the aecial stage on the barberry, and that 

 its removal in the grain belt will very materially increase the pro- 

 duction of wheat, oats and barley. Wherever the barberry occurred 

 there was much rust on grain and wild grasses, like squirrel tail grass, 

 red top, quack grass, Macoun's wild rye, western wheat grass and 

 in some cases timothy. , 



Department of Botany, 



Iowa State College. 



N 



